Nozzle design for generating fluid streams useful in the manufacture of microelectronic devices

ABSTRACT

Improved nozzle design that discharges fluid streams through a series of nozzle orifices distributed along a length of the nozzle. The present invention may be incorporated into a wide range of microelectronic device manufacturing processes and equipment types for which an array of process streams are desired for treating microelectronic workpieces. The present invention is particularly useful to cryogenically clean microelectronic workpieces.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Applicationhaving Ser. No. 60/627310, filed on Nov. 12, 2004, entitled “NozzleDesign for Generating Fluid Streams Useful in the Manufacture ofMicroelectronic Devices,” the entire disclosure of which is incorporatedherein by reference for all purposes.

TECHNICAL FIELD

The present invention relates to equipment and methods for generatingstreams of cryogenic material that may be used in the manufacture ofmicroelectronic devices. More specifically, the present inventionrelates to equipment and methods in which cryogenic material isdispensed through a nozzle including a plurality of orifices. Thepresent invention is particularly useful for efficiently generating acryogenic aerosol to clean particles from a microelectronic device withgood particle removal efficiency and reduced damage of sensitivemicroelectronic structures.

BACKGROUND

The manufacture of microelectronic devices is complex and involvesseveral process steps. Many of these steps involve applying one or morestreams of fluid and/or particles (e.g., cryogenic cleaning fluids,particles, crystals, etc.) onto a workpiece surface in order to carryout one or more of etching, cleaning, stripping, rinsing, and the like.Often, it may be important to ensure that the fluid is directed onto theworkpiece surface as efficiently as possible to help optimize processperformance without damaging microelectronic structures.Cryogenic-aerosol cleaning of microelectronic workpieces is oneillustrative area of concern.

Cryogenic-aerosol cleaning of wafers generally is a “dry” cleaningalternative to more conventional wet chemical cleans for particle andfilm residue removal. This technique is of particular interest inback-end-of-line applications in which wet chemicals might potentiallycorrode device features such as metal lines. Cryogenic-aerosol cleaningis able to use non-corrosive, inert substances such as argon, nitrogen,carbon dioxide, and/or the like, as the cleaning medium. Conventionally,the cleaning mechanisms are mechanical rather than chemical. The processis therefore environmentally friendly and device-safe.

A schematic drawing of an illustrative cryogenic cleaning process isshown in FIG. 1. A cryogenic apparatus 1 includes a chuck (not shown)that supports a microelectronic workpiece 1 a. A nozzle 2 extends acrossworkpiece 1 a. An array of cryogenic aerosol streams 3 issue from aplurality of nozzle orifices (not shown) of nozzle 2. The streams 3include aerosol crystals 3 a. These streams 3 of particles 3 a impingeupon the surface of workpiece 1 a, dislodging contaminants 4 adhering tothe workpiece surface. The surface may be flat or patterned. Typicalcontaminants 4 might include one or more of film or particle residuegenerated as a result of etching and ashing processes. Nozzle 2 and thechuck move relative to each other to ensure that the streams 3 clean theentirety of surface of workpiece 1 a. In the particular approach of FIG.1, nozzle 2 is stationary, while the chuck, and hence workpiece 1 a,move so that the entire surface of workpiece 1 a is cleaned by movementunderneath nozzle 2. Of course, in other embodiments, the chuck could bestationary while nozzle 2 moves. In other embodiments, suitable relativemovement may be obtained if both the chuck and nozzle 2 move relative toeach other. For example, U.S. Pat. No. 5,942,037 describes a system thathas a movable chuck and a rotatable and translatable nozzle.

The formation of cryogenic aerosol is an interesting process. Thecryogenic aerosol is formed by the rapid cryogenic expansion of asuitable fluid discharged through the array of nozzle orifices. Thefluid is generally a liquid, gas, or mixture of one or more materials.Exemplary materials include nitrogen, argon, carbon dioxide, water, ormixtures of these. The fluid enters the nozzle orifices at one pressure(e.g., 80 psia) and exits into a chamber maintained at a considerablylower pressure (typically below 1 psia). The resultant expansion of thefluid results in the formation of cryogenic, solid, or solid-liquidparticle clusters due to expansive cooling. Further discussion ofaerosol formation mechanisms can be found in U.S. Pat. No. 5,942,037; N.Narayanswami, “A Theoretical Analysis of Wafer Cleaning Using aCryogenic Aerosol,” J. of the Electrochemical Society, 146-2:767-774(1999); N. Narayanswami et al., “Development and Optimization of aCryogenic Aerosol Based Wafer Cleaning System,” 28th Annual Meeting ofthe Fine Particle Society Proceedings (1998); and N. Narayanswami etal., “Particle Removal Mechanisms in Cryogenic-Aerosol-Based WaferCleaning,” FSI International Document No. 1133-TRS-0499 (1999).

U.S. Pat. Nos. 4,747,421 and 4,806,171 describe an apparatus forcleaning substrates using CO₂ aerosol particles. U.S. Pat. Nos.4,974,375 and 5,009,240 describe sandblasting devices that use iceparticles generated using water. U.S. Pat. Nos. 5,062,898, and5,209,028, and 5,294,261 describe the use of cryogenic aerosols forsurface cleaning. Borden et. al., in a paper presented at the UltracleanManufacturing Conference, pp. 55-60, October 1994, describes the use ofCO₂ snow jet spray in silicon wafer cleaning.

Contaminant particle removal efficiency is an important criterion forassessing the performance of a cryogenic cleaning process. Contaminantparticle removal efficiency refers to the percentage of particles thatare removed as a result of cryogenic aerosol cleaning. Particle removalefficiency characteristics are often viewed separately for particleswithin different size ranges, because it is important that particleremoval efficiency independently satisfy desired performancespecifications for both large and small particles.

Because cryogenic cleaning directs aerosol crystals upon a workpiecesurface to dislodge contaminant particles, device structures on theworkpiece surface can be sometimes physically damaged by the particles.This is more of a concern with regard to smaller, more sensitivefeatures. Increasing miniaturization of device features has causedcryogenic damage to become more of a concern. Such damage may include,for example, broken polysilicon lines, and the like. In any case, suchdamage generally affects further processing of the device structure orsome performance aspect of the device itself. Given the increasingminiaturization of microelectronic structures, even the presence of verysmall particles or damaged regions can significantly impair or ruin theperformance of the resultant microelectronic device. Thus, it isdesirable to have a cryogenic cleaning process that has a high particleremoval efficiency with minimal or substantially no damage to devicestructures.

SUMMARY

The present invention provides an improved cryogenic cleaning nozzledesign and cryogenic cleaning processes that can provide a high particleremoval efficiency with minimal or substantially no damage to devicestructures being cleaned. Nozzles and methods in accordance with thepresent invention are particularly useful for removing small particlesthat often require greater energy or force to remove without damagingsensitive structures. A nozzle in accordance with the present inventionmay be incorporated into a wide range of microelectronic devicemanufacturing processes and equipment types for which high particleremoval efficiency with minimal or substantial, no damage in treatingmicroelectronic workpieces is desired.

Generally, a nozzle in accordance with the present invention includesplural nozzle orifices distributed along a length of the nozzle. Thenozzle orifices are preferably formed by an electrical dischargemachining (EDM) process and are smaller in size, have smoother walls andedges, and have less variation in diameter than previously known nozzleorifice designs. Smaller nozzle orifices produce smaller droplets withgreater size uniformity. Smoother orifices reduce turbulence in theaerosol as it leaves the orifice resulting in more uniform dropletformation. As such, smaller aerosol crystals having a more uniformparticle size distribution can be formed. Moreover, smaller aerosolcrystals generally cause less damage to device structure than largeraerosol crystals. A nozzle having nozzle orifices with suchcharacteristics in accordance with the present invention provides highparticle removal efficiency with little or no damage to devicestructures. Also, a nozzle having nozzle orifices formed by EDM aregenerally cleaner in that such orifices have less contamination orresidual particulate matter resulting from the manufacturing process.One advantage of this is that nozzles in accordance with the presentinvention generally need less operating time to clean up the nozzles andeliminate particles that may come off of the nozzles during operation.

In one aspect of the present invention, a nozzle for use in an apparatusfor treating a surface of a microelectronic workpiece is provided. Thenozzle comprises a body portion having an outside wall that defines aninside cavity of the body portion. The nozzle also includes a pluralityof nozzle orifices distributed along a length of the body portion. Thenozzle orifices provide a path through the outside wall of the bodyportion. In accordance with the present invention at least two of theplurality of nozzle orifices have a diameter less than 0.0045 inches.Preferably the plurality of nozzle orifices are formed by electricaldischarging machining a plurality of openings through the outside wallof the body portion.

In another aspect of the present invention, an apparatus for treating asurface of a microelectronic workpiece is provided. The apparatuscomprises at least one nozzle. The nozzle comprises a body portionhaving an outside wall that defines an inside cavity of the bodyportion. The nozzle also includes a plurality of nozzle orificesdistributed along a length of the body portion. The nozzle orificesprovide a path through the outside wall of the body portion. Inaccordance with the present invention at least two of the plurality ofnozzle orifices have a diameter less than 0.0045 inches. Preferably theplurality of nozzle orifices are formed by electrical dischargingmachining a plurality of openings through the outside wall of the bodyportion.

In another aspect of the present invention, an apparatus for treating asurface of a microelectronic workpiece is provided. The apparatuscomprises a treatment chamber in which a microelectronic workpiece ispositioned for treatment. The apparatus also comprises a nozzle at leastpartially positioned in the treatment chamber. The nozzle is operativelypositioned relative to the microelectronic workpiece. The nozzlecomprises a plurality of nozzle orifices distributed along a length ofthe nozzle in a manner effective to aim the plurality of nozzle orificestoward the microelectronic workpiece. In accordance with the presentinvention at least two of the plurality of nozzle orifices have adiameter less than 0.0045 inches. Preferably the plurality of nozzleorifices are formed by electrical discharging machining a plurality ofopenings through the outside wall of the body portion.

In another aspect of the present invention, a method of treating asurface of a microelectronic workpiece is provided. The method comprisesthe steps of providing an apparatus having a nozzle for treating asurface of a microelectronic workpiece and causing a process fluid to becryogenically discharged from the nozzle onto the workpiece surface. Theapparatus comprises a treatment chamber in which a microelectronicworkpiece is positioned for treatment and a nozzle at least partiallypositioned in the treatment chamber and operatively positioned relativeto the microelectronic workpiece. The nozzle comprises a plurality ofnozzle orifices distributed along a length of the nozzle in a mannereffective to aim the plurality of nozzle orifices toward themicroelectronic workpiece wherein at least two of the nozzle orificeshave a diameter less than 0.0045 inches.

In yet another aspect of the present invention a method of making anozzle for use in an apparatus for treating a surface of amicroelectronic workpiece is provided. The method comprises the steps ofproviding a body portion comprising a wall that defines an inside cavityof the body portion and forming a plurality of nozzle orificesdistributed along a length of the body portion that provide a paththrough the outside wall of the body portion wherein at least two of theplurality of nozzle orifices have a diameter less than 0.0045 inches.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned and other advantages of the present invention, andthe manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of the embodiments of the invention taken in conjunctionwith the accompanying drawings, wherein:

FIG. 1 is a schematic view of a conventional cryogenic aerosol systemfor cleaning the surface of a silicon wafer;

FIG. 2 is a side schematic view of a cryogenic cleaning system of thepresent invention;

FIG. 3 is a schematic side view of a substrate moving to the leftrelative to a nozzle of the present invention and showing the angle ofimpingement of a stream and the spray distance between the nozzle andthe substrate surface;

FIG. 4 is a side view of a nozzle of the present invention showing alinear array of nozzle orifices distributed along the length of thenozzle;

FIG. 5 is a side view of the nozzle of FIG. 4 that is rotated by 90degrees radially from the view of FIG. 4, wherein the outer tube (shownby the dashed lines) is removed and the inner tube is shown as having alinear array of orifices distributed along its length;

FIG. 6 is a partial cross-section view of the nozzle of FIG. 4; and

FIG. 7 is a partial cross-section view of the nozzle of FIG. 4 takenalong line 7-7.

DETAILED DESCRIPTION

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

The principles of the present invention are advantageously incorporatedinto cryogenic cleaning processes and, in fact, offer improved cleaningprocesses having high particle removal efficiency with reduced orsubstantially eliminated damage to device structures in this context.Using unconventionally fine nozzle orifices, preferably made using EDMtechniques, is an important aspect of this improvement. In aconventional cryogenic cleaning apparatus, cleaning fluid iscryogenically discharged onto a workpiece surface through an array oforifices. Conventionally, the resultant jets of cryogenically dischargedmaterial tend to form aerosol crystals that are relatively large withrespect to the device structures being cleaned. Such large aerosolparticles can provide efficient cleaning with regard to some kinds ofrelatively large particles. But, to provide adequate particle removalefficiency for smaller particles, the larger particles need to bedischarged with more energy thereby increasing the risk of damaging thedevice structures being cleaned. In accordance with the presentinvention, nozzle orifices that are smaller in diameter and havesmoother walls and edges provide smaller aerosol crystals and damage canbe reduced while maintaining high particle removal efficiency. This isbecause even though decreasing the nozzle orifice diameter generallyreduces the overall fluid conductivity of a nozzle having a given numberof orifices, more nozzle orifices can be used in the same amount ofspace. Thus, a desired fluid conductivity for providing high particleremoval efficiency can be provided for a nozzle with smaller nozzleorifices by increasing the number of nozzle orifices. Preferably, inaccordance with the present invention, EDM is used to form nozzleorifices because EDM can provide nozzle orifices that are smaller indiameter and that have smoother walls and edges than can be achievedwith other techniques such a laser drilling.

In order to more concretely illustrate the invention, the invention willnow be described in the context of an enhancement to one representativecryogenic cleaning tool commercially available under the tradedesignation ARIES from FSI International, Inc., Chaska, Minn. Referringnow to FIG. 2, wherein like numerals represent like componentsthroughout the several Figures, an apparatus 10 is illustrated for thetreatment of the surface of an object, such as a microelectronicworkpiece 12. The present invention is useful for treating any type ofmicroelectronics workpiece, including but not limited to those providedduring any stage of the manufacturing of integrated circuits, flat paneldisplays, hard drives, multiple chip modules, and the like.Additionally, the invention is useful for treating masks used formicrolithography processes including x-ray masks, and any semiconductorsubstrates including but not limited to gallium arsenide wafers orwafers comprising silicon.

Apparatus 10 basically comprises a movable chuck 14 that supports themicroelectronic workpiece 12 within an aerosol chamber 16 and a nozzle18. The nozzle 18 may be rotatably adjustable and translatable inaccordance with U.S. Pat. No. 5,942,037. The apparatus 10 is used fortreating a surface 13 of the substrate, e.g. microelectronic workpiece12. Such treatment can be any coating, cleaning, or the like treatmentwherein the nozzle 18 provides an aerosol, liquid or gas to impingesurface 13. For the purposes of a specific description, the apparatus 10will be described as a cryogenic aerosol cleaning apparatus used forcleaning contaminants from the surface of a silicon wafer.

The illustrated chuck 14 is preferably of the type exhibiting a linearmovement within a predetermined range to move the entire side of theworkpiece 12 through the stream discharged from nozzle 18. The presentinvention is also applicable to systems utilizing rotational chucks (notshown) whereby rotary movement of the workpiece 12 is produced in orderto impinge its surface with the streams from the nozzle 18.Alternatively, in accordance with one embodiment of the presentinvention, the nozzle may be translatable in the direction parallel tothe surface of the wafer. Such translation may be in addition tomovement of the chuck, or independent from movement of the chuck whilethe chuck and the wafer remain stationary to accomplish a similarresult. The term chuck is used to mean a device that functionallysupports or otherwise holds the object to be treated. In the case wherethe chuck moves linearly or rotationally, the chuck also includes theappropriate slide or guide mechanism or turntable components. However,where the chuck is stationary, it may be merely a functional supportmechanism.

The apparatus 10 is particularly applicable for cryogenic aerosolcleaning used for cleaning contaminants from microelectronic devicesduring any desired stage of processing such devices. Cryogenic aerosolsmay be derived from a wide range of one or more suitable materials.Examples include argon, nitrogen, carbon dioxide, and/or water as wellas mixtures thereof. For example, mixtures of argon and nitrogen may beused. Specific examples of argon cryogenic aerosols combined withnitrogen are disclosed in U.S. Pat. Nos. 5,062,898, 5,209,028 and5,294,261, all to McDermott et al, and U.S. Pat. No. 5,377,911 to Baueret al, the entire disclosures of each of which are hereby incorporatedby reference for all purposes. Nitrogen alone is presently preferredwhen treating smaller and generally has at least two advantages overargon/nitrogen mixtures. First, nitrogen aerosol ice is smaller in sizethan argon/nitrogen aerosol ice. Second, the molecular mass of argon isgreater than the molecular mass of nitrogen. As a consequence, cryogenaerosols derived from nitrogen have a lesser tendency to damagestructures but can be discharged with enough energy to achieve goodparticle removal efficiency with regard to small microelectronicfeatures.

As shown best in FIG. 2, the aerosol chamber 16 defines an enclosedinterior space having an exhaust duct 20. Within the aerosol chamber 16,the movable chuck 14 is provided. The movable chuck 14 includes asurface for supporting a microelectronic workpiece 12 thereon and ismovably supported so that the surface 13 of the microelectronicworkpiece 12 to be treated can be completely moved through theimpingement area of the nozzle 18. Movable chuck 14 may include anyconventional mechanism for securing the microelectronic workpiece 12 toits surface facing nozzle 18, such as by vacuum openings that open tothe supporting surface for holding the microelectronic workpiece 12against it. Mechanical fasteners or clips, suction devices, bemovillistyle components, electrostatic devices and electromagnetic devices alsoare known for fastening the wafer to the chuck. These and others may beutilized. The movable chuck 14 is further supported within the aerosolchamber 16 to provide its necessary movement. In the particularembodiment of apparatus 10 shown, slides and guiding mechanisms areutilized to define the path of and facilitate movement of the movablechuck 14. Moreover, an actuating mechanism 22 may be utilized to impartthe movement to the movable chuck 14 along its guide path. Actuatormechanism 22 may comprise any conventional electric, mechanical,electromechanical, hydraulic, pneumatic, or the like actuator mechanism.The actuator mechanism 22 should have a range of motion sufficient thatthe surface 13 of microelectronic workpiece 12 can be moved entirelythrough the impingement area. An actuator rod 24 may be connectedbetween the actuator mechanism 22 and the movable chuck 14, and may alsoinclude a vacuum passage for providing the vacuum to the surface of themovable chuck 14 for securing the microelectronic workpiece 12, asdiscussed above.

To control the fluid dynamics within the aerosol chamber 16, a flowseparator comprising a baffle plate 34 is preferably connected to an endof the movable chuck 14 and to extend into the exhaust duct 20.Additionally, a shroud 36 is provided within the aerosol chamber 16 andcomprises a plate connected to the aerosol chamber 16, such as its upperwall, for controlling flow around the nozzle 18. The controlling of thefluid dynamics within the aerosol chamber 16 by the baffle plate 34 andthe shroud 36 are more fully described in U.S. Pat. No. 5,810,942. Onepurpose is to divide the post-impingement flow into positive streams Cand D for preventing recontamination.

Nozzle 18 of the present invention is at least partially supportedwithin the aerosol chamber 16 in a manner effective to dischargecryogenic aerosol onto workpiece 12 at a desired impingement angle.Optionally, in accordance with U.S. Pat. No. 5,942,037, nozzle 18 may berotatably adjustable as indicated by arrow A and translatable along thedirection of arrow B to adjust the spacing between nozzle 18 and thesurface 13 of the workpiece 12. Nozzle 18 is connected with a supplyline 26, which itself may be further connected with discreet supplylines 28 and 30 connected with the actual gas or liquid supplies ofargon, nitrogen, or the like, as desired.

Also shown in FIG. 2, a make-up gas, preferably an inert gas such asnitrogen can be introduced into the aerosol chamber 16 at one or morelocations indicated by way of supply conduits 38. Although notnecessary, such make-up gas is preferably introduced at the top and/orbottom of the aerosol chamber 16 at the other side thereof away from theexhaust. One reason for the use of the make-up gas is to compensate ormake-up for slight pressure deviations (in the order of 5 to 10 percent)within the aerosol chamber caused by instabilities in the nozzle andpressure controls. By supplying the make-up gas, local pressuredifferentials are minimized and the positive overall pressure flow fromthe left to the right that is generated by the action of the aerosolstreams, as illustrated in FIG. 2, is maintained. The make-up gas can beintroduced into the aerosol chamber 16 through slots provided throughthe top and bottom walls of the aerosol chamber 16. Conventional gassupply techniques can be used. Moreover, it is contemplated that reducedvacuum levels in the chamber 16 may provide improvements in particleremoval efficiency or may help to reduce damage. For example, see U.S.Pat. No. 5,961,732 to Patrin et al., the entire disclosure of which isincorporated by reference herein by reference for all purposes.

With reference to FIG. 3, the orientation of orifices 40 relative toworkpiece 12 defines the angle of impingement a of the substance that isused to treat the surface 13 of the workpiece 12. In the case of acryogenic cleaning apparatus, the substance preferably comprises thefrozen cryogenic crystals and gas stream. Optionally, in accordance withU.S. Pat. No. 5,942,037, the nozzle 18 may be rotatably mounted withinthe aerosol chamber 16 so that the angle α can be varied depending onthe desired cleaning angle. Thus, the nozzle is useful or more efficientin a wider range of applications. Specifically, the processing ofsubstrates including deep trenches and other surface features may bemore thoroughly accomplished by orienting the aerosol spray directionmore perpendicular to the substrate surface where α is 45 degrees to 90degrees. For processing a very flat surface, the aerosol spray may beprovided at a very shallow grazing angle that is close to an angle α ofnear 0 degrees to 45 degrees. The angle α may be anywhere between near 0degrees and 90 degrees depending on the application. Depending on thesurface features of the substrate, e.g. workpiece 12, the angle α may bealtered from substrate to substrate or during the cleaning of a singlesubstrate.

Preferably, the nozzle 18 of the present invention is also adjustabletoward or away from the surface 13. The distance x (see FIG. 3) betweenthe lower edge of the nozzle and the substrate surface can be adjustedto optimize any specific process. Moreover, with substrates of varyingthicknesses, it is possible to manipulate the spray nozzle 18 tomaintain a fixed spray travel distance x to the substrate surface overthe variable thickness substrate surface.

Nozzle 18, in accordance with the present invention, is illustrated inmore detail in FIGS. 4 through 7. Generally, the nozzle 18 comprises anouter tube 90, an inner tube 92, an end cap 94, an end cap 95 and afitting 96, which preferably is a part of a VCR fitting as discussed inU.S. Pat. No. 5,942,037 for connection with a supply tube. As shown inFIG. 9, the fitting 96 includes an internal passage 98 that opens from aside of the fitting 96, as illustrated, to communicate with the supply(not shown) of material from which cryogenic aerosol will be derived. Atthe other end of the fitting 96, a tube portion 100 is provided throughwhich the passage 98 also passes. Surrounding the tube portion 100, theouter tube 90 is connected to the surface 102 of the fitting 96.Preferably, the outer tube 90 and the tube portion 100 areconcentrically arranged. The outer tube 90 can be conventionallyconnected with surface 102 by welding. The inner tube 92 is preferablybutted with and connected to the tube portion 100, such as by welding.At the other end of the nozzle 18, the end cap 95 is sealingly connectedto the end of the inner tube 92 and is nested within the end cap 94 thatseals the end of the outer tube 90 and supports both the inner and outertubes 92 and 90, respectively. Preferably, end cap 94 maintains theconcentric relationship of the outer tube 90 and inner tube 92.

By this construction, a first cavity 104 is defined within the outertube 90 by its internal surface 91, the outer surface 93 of the innertube 92, the surface 102 of the fitting 96 and the end cap 94. A secondinternal cavity 106 is also defined within the inner tube 92 and thetube portion 100 of fitting 96 as defined by the interior surfacesthereof and the end cap 95.

The inner tube 92 is preferably provided with a series of longitudinallyaligned orifices 108 as can be seen best in FIG. 6. The orifices 108need not be arranged in this manner, however, and in some cases so notneed to be aligned. For example, some orifices 108 may be radiallydisplaced by 180 degrees from others. The orifices 108 providecommunication between the second internal cavity 106 and the firstinternal cavity 104. The jet impingement orifices 40 are provided in alongitudinally aligned series through the outer tube 90 to providecommunication from the first internal cavity 104 and the outside of thenozzle 18. More specifically, the jet impingement orifices 40 direct thedischarged material therein toward the workpiece 12, in the directionand angle of impingement as discussed above and shown in FIG. 3.

In accordance with the present invention, inner orifices 108 aredesirably radially angularly offset with respect to orifices 40.Preferably, the inner orifices 108 are angularly offset from theorifices 40 by an angle ω in the range of 45 to 180 degrees, mostpreferably about 90 degrees.

As noted above, smaller orifices provide smaller aerosol crystals, whichcan help to minimize damage to device structures being cleaned. Inaccordance with the present invention, the orifices 40 are preferablyformed by EDM. It is noted that any known or future developed materialremoval process that can provide orifices having characteristics similarto those achieved by EDM may be used. EDM is a thermal erosion processin which material is removed by a series of recurring electricaldischarges between an electrode and a workpiece in the presence of adielectric fluid. By using EDM, the orifices 40 can be made in desiredfine sizes and with smoother walls and edges than can be achieved withother material removal processes, such as by laser drilling, forexample. Moreover, smoother walls and edges can help to minimizeturbulence, which also helps to provide smaller aerosol crystals andalso helps to improve the size uniformity of such aerosol crystals. Allof these can help to minimize or substantially eliminate damage todevice structures being cleaned while maintaining high particle removalefficiency.

The size of an orifice such as the orifice 40 can be characterized inany desired way. For example, the diameter of the orifice 40 at eitherside of the orifice 40 as formed through the wall of the tube 90 can bemeasured and used to identify the diameter of the orifice 40.Measurement of a small diameter orifice can be accomplished by usingoptical microscopy or scanning electron microscopy or the like. Ifmicroscopy techniques are used to measure the diameter of the orifice40, the diameter of the orifice 40 at the outside surface of the tube 90is preferably used to characterize the orifice 40. If the diameter ofthe orifice 40 is measurable at the inside surface of the tube 90, suchas by being viewable by a microscope or the like, the diameter of theorifice 40 at the inside surface of the tube 90 may be used, togetherwith or independently from the diameter of the orifice 40 at the outsidesurface of the tube 40. For example, if the diameter of the orifice 40changes through the wall of the tube 40, an average of the insidesurface and outside surface diameters may be used to characterize thediameter of the orifice 40. Moreover, other factors may be used tocharacterize the orifice 40 such as angle of the wall of the orificeitself, the area of either side of the orifice, as well as the major andminor diameters of the orifice. Holes are measured with an opticalmicroscope having a calibrated eyepiece reticle scale or a microscopewith a stage micrometer, or by using magnifying optical comparator.

In one exemplary embodiment, the orifices 40 of the nozzle 18 are formedby EDM and have a diameter that is less than 0.0050 inches. Morepreferably, the orifices 40 have a diameter that is less than 0.0030inches and even more preferably less than 0.0025 inches. Preferably, forany given orifice diameter, the tolerance on the diameter is plus orminus 0.0005 inches and more preferably 0.0002 inches. Any number oforifices 40 may be used to achieve any desired fluid conductivity forthe nozzle 18 as mentioned above. For example, where the orifices 40have a diameter of 0.0025 inches plus or minus 0.0002 inches, theorifices 40 may be spaced apart, on center, by 0.0283 inches (about 35orifices per inch). The number of orifices 40 may be determined byconsidering the size of the microelectronics device desired to betreated. In any case nozzle 18 is preferably designed so that theorifices 40 are as small as possible without reducing particle removalefficiency or increasing damage.

The present invention will now be described with reference to thefollowing illustrative examples.

1. Experimental Procedure:

A. Equipment: TABLE 1 ANTARES ® CX 200 mm Advanced Cleaning System MSP2300 Particle Deposition System Process Monitor Wafers SiO2 ChallengeWafers (described below) Sematech Poly Line Damage Assessment Wafer(Modified as described below) Tencor TBI-SP1 Optical Microscope FSI Zeta200 mm Tool

Nozzles Outer Wall Number of Nozzle Thickness Holes Hole Size Holes MadeBy Nozzle_1 0.010 129 >0.0045″ Laser Drilling (comparative) Nozzle_20.010 129 0.0045″ EDM Nozzle_3 0.020 129 0.0045″ EDM Nozzle_4 0.010 4180.0025″ EDMB. SiN Challenge Wafer Prep Procedure:

Twenty SiO2 challenge wafers were used in this experiment. A challengewafer is a wafer that has had particles purposely deposited on thesurface the wafer so that the wafer can be cleaned and the cleaningefficiency of a particular process can be determined. A summary of thepre-clean, contamination, and processing sequences for these wafers isgiven below.

1. Clean wafers in an FSI Zeta 200 mm tool with the initial wafer cleanrecipe (IWC). This is a wet clean of the wafers prior to depositingparticles. The IWC uses a sulfuric/hydrogen peroxide clean followed byan ammonium hydroxide/hydrogen peroxide clean.

2. Measure wafers on Tenecor TB1-SP1: Recipe “SPC0.09HT_cx”—high speed.This recipe is a standard SP1/TB1 high throughput particle measurementrecipe in the oblique mode for particles >/=90 nm.

3. Contaminate wafers.

3a. Use MSP 2300 Particle Deposition System to “full” deposit SiO2particles at >0.09 microns.

4. Measure wafers on Tenecor TB1-SP1: Recipe “SPC0.09HT_cx”—high speed.

5. Run experiment in ANTARES®CX-200 using test nozzles.

6. Measure wafers on Tenecor TB1-SP1: Recipe “SPC0.09HT_cx”—high speed.There were an average of 4876 initial SiO2 particles at >0.09 microns oneach of the SiO2 challenge wafers.

C. Preparation of Poly Line Damage Assessment Wafer:

A poly line damage assessment wafer was obtained from Sematech. The linewidths and spaces were modified using a wet isotropic etch in a Magellantool to achieve the desired final line widths. Measurements of linewidths and spaces were verified using the Applied Materials SEM VisionInstrument. The poly line height was approximately 225 angstroms. Thecell containing the inspected poly lines was named “Line Cell.” Includedin this cell were five blocks labeled A, B, C, D, and E. Each blockconsisted of various line and space widths that can be found in Table 6.Each block was approximately 4 mm in length. Two of these blocks wereinspected for each damage assessment test. The wafer was orientated suchthat the cells containing the poly lines would run perpendicular to theaerosol. Experience has shown this orientation results in the mostdamage.

D. Experimental Design:

The experiment was designed to determine particle adder performance,particle removal efficiency and poly line damage assessment using anLFLP (Low Flow Low Pressure) (Ar:N2 3:1) @45° Nozzle Angle processrecipe for all nozzles as well as an AspectClean™ (N2Only) @60° NozzleAngle recipe with the standard nozzle only. Regarding the angles, seeFIG. 3 and the description thereof above.

A separate run of three clean bare silicon process monitor wafers wasused to determine particle adder performance for each of the fournozzles. Particle adder performance was evaluated to characterize eachnozzle in terms of how the nozzle added particles to the wafers. Theprocess monitor wafers were run through the ANTARES®CX using theappropriate 2-pass process recipe developed for each nozzle. No dummywafers were used. The wafer numbers used in the tables refer to the slotnumber of the wafer carrier. Particle adders were determined for ≧0.09micron, ≧0.12 micron and ≧0.15 micron particle sizes using the TencorTB1-SP1. See Table 3 for results.

Twenty SiO2 challenge wafers were made with the MSP 2300 ParticleDeposition System, aged for approximately 20-25 days and used forparticle removal efficiency evaluation for all nozzles. Four SiO2challenge wafers were run through the ANTARES®CX using the appropriate2-pass process recipe for each nozzle. In all cases initial, pre, andpost SiO2 particles were measured on the Tencor TB1-SP1 at ≧0.09 micronto determine particle removal efficiency. See Tables 4 and 5 forresults.

An approximately 2″×2″ Sematech poly line damage assessment sample wastaped to a 200 mm silicon substrate and microscopically inspected fordamage with the number of damage sites recorded for each line width. Thesample was then processed through the ANTARES®CX with the standardnozzle using the appropriate 4-pass process recipe. The wafer wasorientated such that the cells containing the poly lines would runperpendicular to the aerosol. Experience has shown this orientationresults in the most damage. The sample was then microscopicallyreinspected for damage with the number of damage sites recorded for eachline width. This procedure was repeated for each of the remainingnozzles and recipes. See Table 6 for results.

The ANTARES®CX process recipes used for each of the nozzles are given inTable 2 below. TABLE 2 Process Recipes for Each Nozzle Dewar Chuck BackChamber Nozzle Gas Set Speed Press PT3 Pressure Angle Gas (slpm)(in/sec) # Passes (psia) (psig) (Torr) (degrees) Nozzle_1: LFLP Argon246 0.9 2 109 72 ± 1 50 45 N2 82 or **CN2 400 4 Nozzle_1: AspectClean ™*N2 360 0.9 2 55 72 ± 1 50 60 N2 135 **CN2 300 Nozzle_2: LFLP Argon 1590.9 2 105 73 ± 1 50 45 N2 53 or **CN2 400 4 Nozzle_3: LFLP Argon 186 0.92 90 74 ± 1 50 45 N2 62 or **CN2 400 4 Nozzle_4: LFLP Argon 168 0.9 2105 72 ± 1 50 45 N2 56 or **CN2 400 4 *Total N2 Flow: N2 Flow thru ArgonMFC (.719 × 360) = 259 slpm N2 Flow thru N2 MFC = 135 slpm 394 slpmTotal N2 Flow **curtain nitrogenE. Results:

Results of the particle adder, SiN particle removal efficiency and polyline damage assessment experiments are shown in Tables 3, 4, 5, and 6below. TABLE 3 Particle Adders Summary Table (2-Passes) Adders NozzleNozzle_1 Nozzle_2 Nozzle_3 Nozzle_4 Recipe LFLP AspectClean LFLP LFLPLFLP Wafer 24 @≧0.09 microns −3 0 1 14 6 Wafer 20 2 10 11 −2 8 Wafer 10−4 4 12 −4 9 Wafer 24 @≧0.12 microns −4 −2 0 7 8 Wafer 20 2 10 7 1 5Wafer 10 −3 1 11 −1 3 Wafer 24 @≧0.15 microns −4 −5 5 7 6 Wafer 20 1 8 4−3 −3 Wafer 10 −6 −1 9 −3 5Particle adder results for all nozzles/recipes were satisfactory at≧0.09 micron.

TABLE 4 SiO2 Particle Removal Efficiency Summary Table (2-Passes)Particle Removal Efficiency @≧0.09 microns Nozzle Nozzle_1 Nozzle_2Nozzle_3 Nozzle_4 Wafer Recipe Wafer LFLP AspectClean ™ LFLP LFLP LFLP20 99.90% 85.41% 96.40% 97.55% 97.31% 18 99.04% 86.47% 96.97% 98.40%98.26% 16 98.95% 87.61% 96.76% 99.02% 98.15% 14 99.70% 87.90% 96.01%98.08% 98.20% Average 99.40% 86.85% 96.53% 98.26% 97.98% Std Dev 0.471.14 0.42 0.62 0.45Highest average PRE obtained with Nozzle_1 using LFLP (Ar:N2 3:1) @45°Nozzle Angle recipe. Lowest PRE obtained with Nozzle_1 usingAspectClean ™ (N2Only) @60° Nozzle Angle recipe.

Individual PRE summary tables per bin size for each of thenozzles/recipes are shown in the Table 5 below. TABLE 5 SiO2 ParticleRemoval Efficiency Summary Table Per Bin Size for Each Wafer 0.09-0.120.12-0.15 0.15-0.20 0.20-0.30 Area Total Rslt Run 1 Summary/LFLP2-pass/Nozzle_1/20 Days Old Wafer 20 99.27% 102.22% 100.05% 100.56%94.59% 99.90% Wafer 18 99.18% 93.53% 99.70% 99.59% 93.75% 99.04% Wafer16 98.48% 98.95% 99.90% 97.35% 96.77% 98.95% Wafer 14 100.43% 96.54%100.20% 97.35% 84.38% 99.70% Average 99.34% 97.81% 99.96% 98.72% 92.37%99.40% Std. Dev. 0.81% 3.68% 0.21% 1.62% 5.48% 0.47% Run 2 Summary/LFLP2-pass/Nozzle_2/20 Days Old Wafer 20 93.03% 97.42% 98.58% 99.19% 100.00%96.40% Wafer 18 94.41% 94.74% 99.35% 99.59% 96.00% 96.97% Wafer 1694.81% 91.69% 99.23% 97.93% 92.86% 96.76% Wafer 14 93.94% 93.24% 98.90%94.72% 93.10% 96.01% Average 94.05% 94.27% 99.02% 97.86% 95.49% 96.53%Std. Dev. 0.76% 2.44% 0.35% 2.20% 3.33% 0.42% Run 3 Summary/LFLP2-pass/Nozzle_3/21 Days Old Wafer 20 94.63% 97.70% 99.56% 100.40% 97.96%97.55% Wafer 18 97.38% 97.57% 99.45% 99.02% 93.55% 98.40% Wafer 1697.90% 99.02% 99.90% 100.21% 95.83% 99.02% Wafer 14 96.91% 94.02% 99.95%98.11% 82.61% 98.08% Average 96.70% 97.08% 99.72% 99.43% 92.49% 98.26%Std. Dev. 1.44% 2.14% 0.25% 1.07% 6.83% 0.62% Run 4 Summary/LFLP2-pass/Nozzle_4/21 Days Old Wafer 20 94.67% 97.91% 99.09% 100.42% 95.65%97.31% Wafer 18 97.50% 94.43% 99.32% 99.20% 100.00% 98.26% Wafer 1697.01% 94.87% 99.54% 100.00% 94.29% 98.15% Wafer 14 96.28% 98.68% 99.85%100.21% 86.67% 98.20% Average 96.37% 96.47% 99.45% 99.96% 94.15% 97.98%Std. Dev. 1.24% 2.14% 0.32% 0.54% 5.55% 0.45% Run 5 Summary/AspectClean2-pass/Nozzle_1/25 Days Old Wafer 20 75.70% 91.19% 92.45% 92.68% 92.31%85.41% Wafer 18 76.72% 92.76% 93.46% 95.79% 92.31% 86.47% Wafer 1678.13% 98.93% 94.42% 92.52% 96.67% 87.61% Wafer 14 80.44% 94.42% 92.96%95.99% 112.50% 87.90% Average 77.75% 94.33% 93.32% 94.24% 98.45% 86.85%Std. Dev. 2.05% 3.34% 0.84% 1.90% 9.59% 1.14%

TABLE 6 Poly Line Damage Assessment Summary Table (4-Passes) # DamageSites Pitch Line Space Nozzle_1 Nozzle_2 Nozzle_3 Nozzle_4 (microns)(microns) (microns) LFLP AspectClean ™ LFLP LFLP LFLP Block A 0.26 0.080.18 133 0 0 3 0 0.28 0.07 0.21 342 1 0 15 0 0.30 0.06 0.24 295 0 1 13 00.34 0.06 0.28 154 0 1 11 0 0.40 0.08 0.32 48 0 0 0 0 0.60 0.12 0.48 7 00 2 0 2.100 0.113 1.20 1278 2 2 40 0 0.083 0.68 Total A 2257 3 4 84 0Block B 0.28 0.09 0.19 11 0 1 0 0 0.30 0.08 0.22 12 0 2 0 0 0.32 0.080.24 22 0 0 0 0 0.36 0.08 0.28 14 0 1 0 0 0.40 0.09 0.31 6 0 0 1 0 0.480.11 0.37 3 0 0 0 0 0.72 0.12 0.60 5 0 0 0 0 2.120 0.115 1.39 814 1 3 260 0.088 0.67 Total B 887 1 7 27 0 Block C 0.30 0.11 0.19 0 0 0 0 0 0.340.10 0.24 4 0 0 0 0 0.36 0.10 0.26 2 0 1 0 0 0.38 0.10 0.28 1 0 0 0 00.42 0.11 0.31 1 0 0 0 0 0.48 0.12 0.36 1 0 0 0 0 0.56 0.13 0.43 0 0 0 00 0.84 0.13 0.71 2 0 0 0 0 2.140 0.121 1.31 808 2 0 17 0 0.090 0.73Total C 819 2 1 17 0 Block D 0.32 0.14 0.18 0 0 0 0 0 0.36 0.12 0.24 1 00 0 0 0.38 0.12 0.26 0 0 0 0 0 0.40 0.12 0.28 1 0 0 1 0 0.44 0.12 0.32 00 0 0 0 0.48 0.13 0.35 1 0 1 0 0 0.54 0.14 0.40 0 0 0 0 0 0.64 0.15 0.490 0 0 0 0 0.96 0.14 0.92 0 0 0 0 0 2.160 0.131 1.33 480 1 0 14 0 0.0850.70 Total D 483 1 1 15 0 Block E 0.36 0.15 0.21 0 0 0 0 0 0.40 0.140.26 0 0 0 1 0 0.44 0.14 0.30 0 0 0 0 0 0.46 0.14 0.32 0 0 0 0 0 0.520.15 0.37 0 0 1 0 0 0.54 0.15 0.39 0 0 0 0 0 0.62 0.16 0.46 0 0 0 0 00.72 0.16 0.56 0 0 0 0 0 1.08 0.16 0.64 0 0 0 0 0 2.180 0.169 1.34 380 00 12 0 0.090 0.60 Total E 380 0 1 13 0 Total Defects per Nozzle 4826 714 156 0Highest number of poly line defects obtained with Nozzle_1 using LFLP(Ar:N2 3:1) @45°Nozzle Angle recipe. Lowest poly line defect numberobtained with Nozzle_4 LFLP (Ar:N2 3:1) @45° Nozzle Angle recipe.F. SUMMARY:

-   -   Particle adder results of the Nozzle_(—)1 processed with the        LFLP (Ar:N2 3:1) recipe and the AspectClean™ (N2Only) @60°        Nozzle Angle recipe as well as Nozzle_(—)2, Nozzle_(—)3, and        Nozzle_(—)4 processed with the LFLP (Ar:N2 3:1) recipes were        satisfactory at ≧0.09 microns.

Average SiN particle removal efficiencies @≧0.09 microns when processingwith the LFLP or AspectClean 2-Pass process recipes are shown in Table7. TABLE 7 SiO2 Particle Removal Efficiency Summary Table ParticleRemoval Efficiency Nozzle Type Recipe @≧0.09 microns Nozzle_1 LFLP99.40% Nozzle_1 AspectClean ™ 86.85% Nozzle_2 LFLP 96.53% Nozzle_3 LFLP98.26% Nozzle_4 LFLP 97.98%

Total instances of Poly Line Damage Sites observed microscopically whenprocessing with the LFLP or AspectClean 4-Pass process recipes are shownin Table 8. TABLE 8 Poly Line Damage Summary Table Total Poly LineNozzle Type Recipe Damage Sites Nozzle_1 LFLP 4826 Nozzle_1AspectClean ™ 7 Nozzle_2 LFLP 14 Nozzle_3 LFLP 156 Nozzle_4 LFLP 0G. Additional Testing:

A damage assessment wafer was processed through the LFLP 2-pass recipeusing Nozzle_(—)4. This was a full wafer with the same structures usedin the tests above. The wafer was sent out for damage analysis. Theresults are presented below in Table 9. TABLE 9 Nozzle Recipe AngleDamage Sites PRE Nzl 4 LFLP 45° 24 98.6 Nzl 1 AspCIn 60° 7 95.16(comparative) Nzl 4 AspCIn 45° 4 91.98 Nzl 4 LFLP 60° 0 97.84

-   -   Two, one day old, wet dipped SiN challenge wafers were processed        with Nozzle_(—)4 through the LFLP 2-pass recipe and LFLP 4-pass        recipe with a 45 degree nozzle angle. This was done to provide a        direct Particle Removal Efficiency comparison between the CX and        ZETA tools. Results were as follows:        -   LFLP 2-pass Nozzle_(—)4: PRE=74% and 75% for CX and Zeta,            respectively.        -   LFLP 4-pass Nozzle_(—)4: PRE=77% and 78% for CX and Zeta,            respectively.

Other embodiments of this invention will be apparent to those skilled inthe art upon consideration of this specification or from practice of theinvention disclosed herein. Various omissions, modifications, andchanges to the principles and embodiments described herein may be madeby one skilled in the art without departing from the true scope andspirit of the invention which is indicated by the following claims.

1. A nozzle for use in an apparatus for treating a surface of a microelectronic workpiece, the nozzle comprising a body portion having an outside wall that defines an inside cavity of the body portion and a plurality of nozzle orifices distributed along a length of the body portion and providing a path through the outside wall of the body portion wherein at least two of the plurality of nozzle orifices have a diameter less than 0.0045 inches.
 2. The nozzle of claim 1, wherein the plurality of nozzle orifices are formed by electrical discharging machining a plurality of openings through the outside wall of the body portion.
 3. The nozzle of claim 1, further comprising a distribution conduit within the inside cavity of the body portion, the distribution conduit comprising a plurality of delivery openings formed though a wall that defines an inside cavity of the distribution conduit and distributed along a length of the distribution conduit.
 4. The nozzle of claim 1 in combination with an apparatus for treating a surface of a microelectronic workpiece.
 5. The combination of claim 4, wherein the plurality of nozzle orifices are formed by electrical discharging machining a plurality of openings through the outside wall of the body portion.
 6. The combination of claim 5, further comprising a distribution conduit within the inside cavity of the body portion, the distribution conduit comprising a plurality of delivery openings formed though a wall that defines an inside cavity of the distribution conduit and distributed along a length of the distribution conduit.
 7. An apparatus for treating a surface of a microelectronic workpiece, the apparatus comprising: a treatment chamber in which a microelectronic workpiece is positioned for treatment; a nozzle at least partially positioned in the treatment chamber and operatively positioned relative to the microelectronic workpiece, the nozzle comprising a plurality of nozzle orifices distributed along a length of the nozzle in a manner effective to aim the plurality of nozzle orifices toward the microelectronic workpiece wherein at least two of the nozzle orifices have a diameter less than 0.0045 inches; and a cryogenic material being discharged from the nozzle toward the workpiece.
 8. The nozzle of claim 7, wherein the plurality of nozzle orifices are formed by electrical discharging machining a plurality of openings through a wall of the nozzle.
 9. A method of treating a surface of a workpiece, the method comprising the steps of: providing an apparatus for treating a surface of a microelectronic workpiece, the apparatus comprising: a treatment chamber in which a microelectronic workpiece is positioned for treatment; a nozzle at least partially positioned in the treatment chamber and operatively positioned relative to the microelectronic workpiece, the nozzle comprising a plurality of nozzle orifices distributed along a length of the nozzle and aimed toward the microelectronic workpiece wherein at least two of the nozzle orifices have a diameter less than 0.0045 inches; and, causing a process fluid to be cryogenically discharged from the nozzle orifices onto the workpiece surface.
 10. The method of claim 9, wherein the plurality of nozzle orifices of the nozzle are formed by electrical discharging machining a plurality of openings through a wall of the nozzle.
 11. A method of making a nozzle for use in an apparatus for treating a surface of a microelectronic workpiece, the method comprising the steps of providing a body portion comprising a wall that defines an inside cavity of the body portion and forming a plurality of nozzle orifices distributed along a length of the body portion that provide a path through the outside wall of the body portion wherein at least two of the plurality of nozzle orifices have a diameter less than 0.0045 inches.
 12. The method of claim 11, further comprising the step of forming the plurality of nozzle orifices by electrical discharging machining a plurality of openings through the wall of the nozzle.
 13. The method of claim 11, further comprising the step of providing a distribution conduit within the inside cavity of the body portion, the distribution conduit comprising a plurality of delivery openings formed though a wall that defines an inside cavity of the distribution conduit and distributed along a length of the distribution conduit. 